Line an 8×8 square pan with parchment paper, set aside.
To a double boiler (or set up a double boiler with simmering water in a pot, over a medium-low heat, with a heat safe glass bowl, like pyrex, on top), add chocolate chips and sweetened condensed milk
Heat until melted.
As the mixture starts to melt, stir in vanilla.
This mixture will go from melting to starting to solidify pretty quickly, so once the chocolate chips are mostly melted, immediately pour the mixture into your prepared 8×8 pan.
Smooth out the mixture to the edges of the pan, then sprinkle with Christmas sprinkles.
Cover the fudge with foil or plastic wrap and move to the refrigerator to set.
Allow the fudge to chill for about 4 hours, then cut into small 1-inch squares.